You are absolutely right. Given the same weight rifle, bullet weight, bullet velocity and powder charge the recoil in ft/lbs and recoil velocity will be identical.
In theory yes. However when your shoulder tells you different than you have to decied which you believe.
Don't forget different case designs can effect recoil velocity/acceleration to reach the recoil velocity.
I have not done the recoil figures but 106 grains of AR2213sc/H4831 pushing a 410grain projectile in my Rigby kicks a lot sharper and harder than 96grains of AR2209/H4350 pushing the same projectile and both have the same MV. Yes 10 grains more powder but a slower powder so recoil velocity should be lower, maybe.
So I tried 100 grains of AR2209 and 102 grains of AR2213sc. the 2213sc still had a noticeably sharper kick. The 100grains of 2209 would certainly have produced a higher MV than the 2213sc. Go figure.
After reading this thread I have a want for a 404J even though I have a 416Rigby. Now I have an M17 action and a 458CZ550 (That wont be used as a 458WM) which action do I use. Or do I go have a cuppa tea, a lay down and let the urge go.